List of monsters you can create with info

[Mastertrek]

There's no way to complete Pal List until Post-game, so don't worry about making every monster possible at this point. Focus on making Suzaku (you need to create it once to get something you will need, but once created, can be used to power up your Team if you don't want to use it in team.)

Yes, Sword Goblin + a Dark-Element/Type Goblin monster should result in a Dark Goblin.